axmol/core/base/CCEventDispatcher.h

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 Copyright (c) 2013-2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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#ifndef __CC_EVENT_DISPATCHER_H__
#define __CC_EVENT_DISPATCHER_H__

#include <functional>
#include <string>
#include <unordered_map>
#include <vector>
#include <set>

#include "platform/CCPlatformMacros.h"
#include "base/CCEventListener.h"
#include "base/CCEvent.h"
#include "platform/CCStdC.h"

/**
 * @addtogroup base
 * @{
 */

NS_CC_BEGIN

class Event;
class EventTouch;
class Node;
class EventCustom;
class EventListenerCustom;

/** @class EventDispatcher
* @brief This class manages event listener subscriptions
and event dispatching.

The EventListener list is managed in such a way that
event listeners can be added and removed even
from within an EventListener, while events are being
dispatched.
@js NA
*/
class CC_DLL EventDispatcher : public Ref
{
public:
    // Adds event listener.

    /** Adds a event listener for a specified event with the priority of scene graph.
     *  @param listener The listener of a specified event.
     *  @param node The priority of the listener is based on the draw order of this node.
     *  @note  The priority of scene graph will be fixed value 0. So the order of listener item
     *          in the vector will be ' <0, scene graph (0 priority), >0'.
     */
    void addEventListenerWithSceneGraphPriority(EventListener* listener, Node* node);

    /** Adds a event listener for a specified event with the fixed priority.
     *  @param listener The listener of a specified event.
     *  @param fixedPriority The fixed priority of the listener.
     *  @note A lower priority will be called before the ones that have a higher value.
     *        0 priority is forbidden for fixed priority since it's used for scene graph based priority.
     */
    void addEventListenerWithFixedPriority(EventListener* listener, int fixedPriority);

    /** Adds a Custom event listener.
     It will use a fixed priority of 1.
     * @param eventName A given name of the event.
     * @param callback A given callback method that associated the event name.
     * @return the generated event. Needed in order to remove the event from the dispatcher
     */
    EventListenerCustom* addCustomEventListener(std::string_view eventName,
                                                const std::function<void(EventCustom*)>& callback);

    /////////////////////////////////////////////

    // Removes event listener

    /** Remove a listener.
     *
     *  @param listener The specified event listener which needs to be removed.
     */
    void removeEventListener(EventListener* listener);

    /** Removes all listeners with the same event listener type.
     *
     * @param listenerType A given event listener type which needs to be removed.
     */
    void removeEventListenersForType(EventListener::Type listenerType);

    /** Removes all listeners which are associated with the specified target.
     *
     * @param target A given target node.
     * @param recursive True if remove recursively, the default value is false.
     */
    void removeEventListenersForTarget(Node* target, bool recursive = false);

    /** Removes all custom listeners with the same event name.
     *
     * @param customEventName A given event listener name which needs to be removed.
     */
    void removeCustomEventListeners(std::string_view customEventName);

    /** Removes all listeners.
     */
    void removeAllEventListeners();

    /////////////////////////////////////////////

    // Pauses / Resumes event listener

    /** Pauses all listeners which are associated the specified target.
     *
     * @param target A given target node.
     * @param recursive True if pause recursively, the default value is false.
     */
    void pauseEventListenersForTarget(Node* target, bool recursive = false);

    /** Resumes all listeners which are associated the specified target.
     *
     * @param target A given target node.
     * @param recursive True if resume recursively, the default value is false.
     */
    void resumeEventListenersForTarget(Node* target, bool recursive = false);

    /////////////////////////////////////////////

    /** Sets listener's priority with fixed value.
     *
     * @param listener A given listener.
     * @param fixedPriority The fixed priority value.
     */
    void setPriority(EventListener* listener, int fixedPriority);

    /** Whether to enable dispatching events.
     *
     * @param isEnabled  True if enable dispatching events.
     */
    void setEnabled(bool isEnabled);

    /** Checks whether dispatching events is enabled.
     *
     * @return True if dispatching events is enabled.
     */
    bool isEnabled() const;

    /////////////////////////////////////////////

    /** Dispatches the event.
     *  Also removes all EventListeners marked for deletion from the
     *  event dispatcher list.
     *
     * @param event The event needs to be dispatched.
     */
    void dispatchEvent(Event* event);

    /** Dispatches a Custom Event with a event name an optional user data.
     *
     * @param eventName The name of the event which needs to be dispatched.
     * @param optionalUserData The optional user data, it's a void*, the default value is nullptr.
     */
    void dispatchCustomEvent(std::string_view eventName, void* optionalUserData = nullptr);

    /** Query whether the specified event listener id has been added.
     *
     * @param listenerID The listenerID of the event listener id.
     *
     * @return True if dispatching events is exist
     */
    bool hasEventListener(std::string_view listenerID) const;

    /////////////////////////////////////////////

    /** Constructor of EventDispatcher.
     */
    EventDispatcher();
    /** Destructor of EventDispatcher.
     */
    ~EventDispatcher();

#if CC_NODE_DEBUG_VERIFY_EVENT_LISTENERS && COCOS2D_DEBUG > 0

    /**
     * To help track down event listener issues in debug builds.
     * Verifies that the node has no event listeners associated with it when destroyed.
     */
    void debugCheckNodeHasNoEventListenersOnDestruction(Node* node);

#endif

protected:
    friend class Node;

    /** Sets the dirty flag for a node. */
    void setDirtyForNode(Node* node);

    /**
     *  The vector to store event listeners with scene graph based priority and fixed priority.
     */
    class EventListenerVector
    {
    public:
        EventListenerVector();
        ~EventListenerVector();
        size_t size() const;
        bool empty() const;

        void push_back(EventListener* item);
        void clearSceneGraphListeners();
        void clearFixedListeners();
        void clear();

        std::vector<EventListener*>* getFixedPriorityListeners() const { return _fixedListeners; }
        std::vector<EventListener*>* getSceneGraphPriorityListeners() const { return _sceneGraphListeners; }
        ssize_t getGt0Index() const { return _gt0Index; }
        void setGt0Index(ssize_t index) { _gt0Index = index; }

    private:
        std::vector<EventListener*>* _fixedListeners;
        std::vector<EventListener*>* _sceneGraphListeners;
        ssize_t _gt0Index;
    };

    /** Adds an event listener with item
     *  @note if it is dispatching event, the added operation will be delayed to the end of current dispatch
     *  @see forceAddEventListener
     */
    void addEventListener(EventListener* listener);

    /** Force adding an event listener
     *  @note force add an event listener which will ignore whether it's in dispatching.
     *  @see addEventListener
     */
    void forceAddEventListener(EventListener* listener);

    /** Gets event the listener list for the event listener type. */
    EventListenerVector* getListeners(std::string_view listenerID) const;

    /** Update dirty flag */
    void updateDirtyFlagForSceneGraph();

    /** Removes all listeners with the same event listener ID */
    void removeEventListenersForListenerID(std::string_view listenerID);

    /** Sort event listener */
    void sortEventListeners(std::string_view listenerID);

    /** Sorts the listeners of specified type by scene graph priority */
    void sortEventListenersOfSceneGraphPriority(std::string_view listenerID, Node* rootNode);

    /** Sorts the listeners of specified type by fixed priority */
    void sortEventListenersOfFixedPriority(std::string_view listenerID);

    /** Updates all listeners
     *  1) Removes all listener items that have been marked as 'removed' when dispatching event.
     *  2) Adds all listener items that have been marked as 'added' when dispatching event.
     */
    void updateListeners(Event* event);

    /** Touch event needs to be processed different with other events since it needs support ALL_AT_ONCE and ONE_BY_NONE
     * mode. */
    void dispatchTouchEvent(EventTouch* event);

    /** Associates node with event listener */
    void associateNodeAndEventListener(Node* node, EventListener* listener);

    /** Dissociates node with event listener */
    void dissociateNodeAndEventListener(Node* node, EventListener* listener);

    /** Dispatches event to listeners with a specified listener type */
    void dispatchEventToListeners(EventListenerVector* listeners, const std::function<bool(EventListener*)>& onEvent);

    /** Special version dispatchEventToListeners for touch/mouse event.
     *
     *  Touch/mouse event process flow different with common event,
     *      for scene graph node listeners, touch event process flow should
     *      order by viewport/camera first, because the touch location convert
     *      to 3D world space is different by different camera.
     *  When listener process touch event, can get current camera by Camera::getVisitingCamera().
     */
    void dispatchTouchEventToListeners(EventListenerVector* listeners,
                                       const std::function<bool(EventListener*)>& onEvent);

    void releaseListener(EventListener* listener);

    /// Priority dirty flag
    enum class DirtyFlag
    {
        NONE                 = 0,
        FIXED_PRIORITY       = 1 << 0,
        SCENE_GRAPH_PRIORITY = 1 << 1,
        ALL                  = FIXED_PRIORITY | SCENE_GRAPH_PRIORITY
    };

    /** Sets the dirty flag for a specified listener ID */
    void setDirty(std::string_view listenerID, DirtyFlag flag);

    /** Walks though scene graph to get the draw order for each node, it's called before sorting event listener with
     * scene graph priority */
    void visitTarget(Node* node, bool isRootNode);

    /** Remove all listeners in _toRemoveListeners list and cleanup */
    void cleanToRemovedListeners();

    /** Listeners map */
    hlookup::string_map<EventListenerVector*> _listenerMap;

    /** The map of dirty flag */
    hlookup::string_map<DirtyFlag> _priorityDirtyFlagMap;

    /** The map of node and event listeners */
    std::unordered_map<Node*, std::vector<EventListener*>*> _nodeListenersMap;

    /** The map of node and its event priority */
    std::unordered_map<Node*, int> _nodePriorityMap;

    /** key: Global Z Order, value: Sorted Nodes */
    std::unordered_map<float, std::vector<Node*>> _globalZOrderNodeMap;

    /** The listeners to be added after dispatching event */
    std::vector<EventListener*> _toAddedListeners;

    /** The listeners to be removed after dispatching event */
    std::vector<EventListener*> _toRemovedListeners;

    /** The nodes were associated with scene graph based priority listeners */
    std::set<Node*> _dirtyNodes;

    /** Whether the dispatcher is dispatching event */
    int _inDispatch;

    /** Whether to enable dispatching event */
    bool _isEnabled;

    int _nodePriorityIndex;

    std::set<std::string> _internalCustomListenerIDs;
};

NS_CC_END

// end of base group
/// @}

#endif  // __CC_EVENT_DISPATCHER_H__